test/java/io/InputStreamReader/GrowAfterEOF.java

/*
 * Copyright (c) 1998, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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 * questions.
 */

/* @test
   @bug 4101707
   @summary Test if fill() will behave correctly at EOF to
            allow file to grow.
*/

import java.io.*;

public class GrowAfterEOF {
    public static void main(String[] args) throws Exception {
        File input = new File(".", "TestEOFInput.txt");
        RandomAccessFile rf = new RandomAccessFile(input, "rw");
        BufferedReader r = new BufferedReader
            (new InputStreamReader(new FileInputStream(input)));

        // write something
        rf.writeBytes("a line");

        // read till the end of file
        while (r.readLine() != null);

        // append to the end of the file
        rf.seek(rf.length());
        rf.writeBytes("new line");

        // now try to read again
        boolean readMore = false;
        while (r.readLine() != null) {
            readMore = true;
        }
        if (!readMore) {
            input.delete();
            throw new Exception("Failed test: unable to read!");
        } else {
            input.delete();
        }
    }
}